Visual field analysis after laser in situ keratomileusis

To evaluate the effects of laser in situ keratomileusis (LASIK) on the patients' visual field. 92 eyes of 46 patients with mild, moderate, and high degrees of myopia were undergone LASIK. Perimetry was performed before and 1 day, 1 month, 3 months, 6 months after LASIK surgery by Humphrey II-750 visual field analysis. The central 30 - 2 fast threshold program was used to examine the change in central 30 degree. Mean defect (MD) and pattern standard deviation (PSD) were record. All operations were performed by an experienced surgeon. Statistical analyses were performed by SPSS using the randomized complete block design ANOVA (two factors analysis of variance). Differences among variables were evaluated by q-test (Student-Newman-Kueuls method). 93.5% patients obtained estimated best correct visual acuity or better at six months after LASIK. No complications were found in the subjects. No difference was found in fundus examinations before and after surgery. Intraocular pressure was normal at all preoperative and postoperative examinations. MD was significant differences among preoperative and postoperative values (P < 0.05, for all comparisons) and was correlated with visual acuity post-LASIK significantly (P < 0.05). While PSD did not show significant differences before and after LASIK (P > 0.05) and was not correlated with visual acuity post-LASIK. The indexes of visual field were not correlated with the degree of myopia and the other surgical parameters (P > 0.05). In current research, no significant visual field change was demonstrated pre-LASIK and post-LASIK after 6 months follow-up. The study suggests that LASIK does not affect the retinal physiological functions.

ABSTRACT&#x0D; Introductions: Laser in situ Keratomileusis (LASIK) is the most common refractive surgery to treat myopia. One of the most common complain after this procedure is blurry near- vision.&#x0D; Objectives: To evaluate the role of accommodation amplitude (AA) in myopic patients before and after LASIK and its effect to blurry near-vision in myopic patients after LASIK&#x0D; Methods: Patients with myopia who underwent LASIK procedure in Sriwijaya Eye Center Hospital from January to February 2018 studied prospectively. AA was assessed before and after LASIK with 1 day, 1 week and 1 month. Myopia degree, intraocular pressure (IOP), age, gender, ablation and corneal profile were also assessed.&#x0D; Results: A total 52 eyes from 32 patients were included. Visual acuity (VA) of all sample were significantly improve in 1 day after LASIK (p 0,001). Mean AA in myopic patients before LASIK 9,25 D and AA 1 day after LASIK were all significantly decrease into 9,00D (p 0,012) which can cause in blurry near- vision after LASIK. In 1 month followed-up, mean AA is significantly improved into 11,00 D (p 0,000) with no complain. Other factor that affect the changing AA were corneal cell density (CD), IOP and AA before LASIK.&#x0D; Conclusions: There is significant AA difference in myopic patients before and after LASIK. Blurry near-vision after LASIK is caused by AA adaptation mechanism after LASIK.

Commentary: Rethinking 10-2 visual fields in early diagnosis of glaucoma for a glided glaucoma practice: The right choice to pick up a feeble noise?

To compare the clinical results of femtosecond (FS) laser in situ keratomileusis (LASIK) in high myopic patients and low myopic patients. This study included 212 myopic eyes undergoing LASIK using a VisuMax 500kHz FS laser. All treated eyes were assigned to one of two groups according to preoperative manifest spherical refraction: low myopia group (A, >-4.0 D) and high myopia group (B, ≤-4.0 D). Uncorrected and corrected distance visual acuity (UDVA, CDVA), refractive errors, and higher-order aberrations (HOAs) were measured preoperatively and 1wk, 1, 3 and 6mo postoperatively. At 6mo of follow-up, 92% and 76% had a UDVA of 20/20 or better in group A and B, respectively (P=0.037) and UDVA was significantly different between two groups (P=0.042). Six and seven percentage lost one line of CDVA in group A and B, respectively (P=0.572) and no eyes in both groups lost more than two lines. Each group had 87% and 76% of treated eyes within ±0.5 D of the intended correction (P=0.186), and 13% and 43% with a change of >0.50 D in spherical equivalent from 1wk to 6mo postoperatively (P=0.005). In terms of postoperative astigmatism, each group had 89.1% and 76.6% within ±0.50 D, respectively and there was significant difference (P=0.006). Group A tends to induce smaller HOAs than group B. FS LASIK is effective and safe for correcting high myopia as well as low myopia. However, high myopic eyes showed more postoperative astigmatism and HOAs which affect visual acuity.

Background: Corneal ectasia is a serious vision-threatening complication of laser-assisted in-situ keratomileusis (LASIK). Objective: The aim of the work was to evaluate the efficacy and safety of ultraviolet A (UVA) irradiation crosslinking in concurrent with LASIK in myopic patient with normal cornea to avoid post LASIK ectasia. Patients and Methods: This Prospective randomized interventional study included 60 eyes of 30 consecutive patient who were scheduled for LASIK surgery, all of them were myopic with normal cornea with no pervious refractive surgery. They were candidate for Combined Topo-Guided LASIK with accelerated CXL. This was done in a private eye hospital between Jun 2018 and Jun 2019. Results: The preoperative uncorrected visual acuity (UCVA) ranged from 0.05- 0.1 with mean 0.075±0.02 and preoperative best corrected visual acuity (BCVA) ranged 0.2- 1.0 with mean 0.58±0.13 and post-operative UCVA at 6 months showed ranged 0.2-1.0 with mean 0.55±0.16, and postoperative UCVA at 1 year showed ranged 0.2-1.0 with mean 0.56±0.13,. The improvement in visual acuity from 0.075±0.02 UCVA preoperatively show statistically significant difference (P > 0.05) because we compared the results with the preoperative BCVA 0.58±0.13 postoperatively at 6 months. However, t-Paired Sample t-test; p-value < 0.05 S. Conclusion: It could be concluded that LASIK combined with a prophylactic CXL intervention appears to provide predictability as well as refractive and keratometric stability. The data reported in this study provide evidence of the safety and efficacy of this approach.

Laser in situ keratomileusis to correct myopia after scleral buckling for retinal detachment

Purpose To evaluate corneal endothelial cells before and after laser-assisted in situ keratomileusis (LASIK) combined with accelerated, high-fluence collagen cross-linking (CXL) in myopic patients. Patients and methods In a prospective comparative nonrandomized interventional case series study, 60 myopic eyes of 30 patients (seven males and 23 females) with age ranged from 18 to 35 years were distributed into two groups. Group A included 30 eyes of 15 patients, treated by LASIK, whereas group B included 30 eyes of 15 patients treated by LASIK associated with high-fluence CXL. All patients were subjected to preoperative and 3- and 6-month postoperative evaluation of corneal endothelial profile using specular microscope. Results Qualitative and quantitative analysis of the corneal endothelial cells comparing the two groups showed statistically significant changes in endothelial cell density (P=0.040) at 3-month follow-up after the procedure, which improved to reach a value close to preoperative values, with no significant changes between the two groups at 6-month follow-up (P=0.081). There was no significant change in polymegathism or coefficient of variation and in the percentage of hexagonal cells (pleomorphism) in each group and in comparing between the two groups at 3- and 6-month follow-up. Conclusions LASIK with high-fluence CXL is safe and has no adverse effect on corneal endothelium.

Long-term Development of Significant Visual Field Defects in Highly Myopic Eyes

To analyze the appearance, incidence, and characteristics of retinal diseases in myopic patients after refractive surgery. We studied retinal disease observed in 9,239 consecutive eyes (5,099 patients) after refractive surgery. Photorefractive keratectomy (PRK) was used to correct myopia in 5,936 eyes (3,184 patients, mean age 30.5 +/- 8.9 years); mean spherical equivalent refraction was -4.71 +/- 2.80 D. Laser in situ keratomileusis (LASIK) was used to correct myopia in 3,009 eyes (1,734 patients, mean age 32.0 +/- 7.8 years); mean spherical equivalent refraction was -13.5 +/- 3.30 D. An anterior chamber phakic intraocular lens (PIOL) was implanted to correct myopia in 294 eyes (181 patients, mean age 32.6 +/- 7.3 yr) with a mean spherical equivalent refraction of -18.5 +/- 5.00 D. Retinal detachment occurred at a mean 53.6 +/- 41.4 months after PRK in 9 eyes (0.15%), 24.6 +/- 20.4 months after LASIK in 11 eyes (0.36%), and 20.5 +/- 17.4 months after anterior chamber PIOL implantation in 12 eyes (4.08%). Choroidal neovascularization occurred a mean 26 months after PRK in 1 eye (0.01%), mean 30.2 +/- 19.3 months after LASIK in 10 eyes (0.33%), and mean 49.0 +/- 33.5 months after PACL implantation in 7 eyes (2.38%). One patient developed a macular hole 12 months after LASIK and another patient developed a macular hemorrhage immediately after LASIK. Epiretinal membrane appeared in one patient 19 months after anterior chamber PIOL implantation. There was no relationship between PRK for myopia and retinal disease. LASIK for correction of myopia was followed by a low incidence of retinal disease; additional study is necessary to assess the true impact of the suction ring in the myopic eye. Implantation of an anterior chamber PIOL to correct high myopia was followed by a low incidence of choroidal neovascularization, a high incidence of retinal detachment, similar to other intraocular interventions in highly myopic patients.

PurposeTo compare the long-term safety and efficacy of laser in situ keratomileusis (LASIK) with Artisan phakic intraocular lens implantation to correct refractive errors after penetrating keratoplasty (PK) for keratoconus.MethodsThis retrospective comparative interventional case series included a total of 33 consecutive keratoconus eyes that had previous PK and received subsequent LASIK (n = 16) or Artisan lens implantation (n = 17) were included in this study. Outcome measures were uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refractive error, and complications.ResultsPostoperatively, the UDVA of ≥20/40 was achieved in none of the LASIK group compared to 62.5% of eyes in the Artisan group (P < 0.001); the respective values for CDVA of ≥20/40 were 87.5 and 94.1% (P = 0.51). Spherical equivalent refraction decreased from − 6.97 ± 1.50 D preoperatively to − 4.20 ± 2.05 D postoperatively in the LASIK group (P < 0.001) and from − 10.79 ± 2.15 D preoperatively to − 2.13 ± 1.23 D postoperatively in the Artisan group (P < 0.001). There was no significant change in the refractive astigmatism in LASIK group (P = 0.30) or Artisan group (P = 0.11). The efficacy and safety indices were significantly better for Artisan (0.82 ± 0.34 and 1.13 ± 0.30, respectively) than for LASIK (0.22 ± 0.17 and 0.85 ± 0.24, respectively, P ≤ 0.006 for both comparisons). While refractive error changed significantly from postoperative year 3 to the final visit in the LASIK group, it remained stable in the Artisan group through follow-up period. No significant complications were observed in any group.ConclusionArtisan lens implantation provided superior and stable visual outcomes compared to LASIK for the management of post PK refractive errors in keratoconus eyes.

Change in the accommodative convergence per unit of accommodation ratio after bilateral laser in situ keratomileusis for myopia in orthotropic patients: Prospective evaluation

Purpose: To evaluate the accuracy of confrontation visual field testing with regard to the density of the visual field defect and its location in the peripheral visual field. Methods: A prospective comparison of confrontation visual field testing with fullthreshold Humphrey automated static perimetry C24-2 or C30-2 was conducted at a university eye center over a 3-month period. Seventy-two patients with a variety of neurologic and ophthalmologic conditions underwent confrontation visual field testing and automated perimetry as a part of their evaluation. One visual field from each patient was analyzed for this study. Results: Confrontation visual field testing yielded an overall sensitivity for detecting an abnormal visual field (full-field analysis) of 63%, when sensitivity of confrontation testing rested on the detection of just one abnormal quadrant. The sensitivity of confrontation testing varied depending on the type of visual field loss present: 51 % for arcuate scotomas, 67% for visual field constriction, 78% for attitudinal scotomas, and 90% for hemianopias. The sensitivity of detecting abnormal visual field quadrants, rather than the full-field analysis, was, however, poor at 38%. The sensitivity of confrontation testing was lower for superior quadrant defects and higher for inferior quadrant defects. The estimated probability of detecting an abnormal visual field quadrant occurring at a —26-decibel sensitivity loss from age-matched healthy patients for superior quadrant defects and a —19-decibel sensitivity loss for inferior quadrant defects was 50%. The increased sensitivity noted for visual field defects and for inferior quadrant defects appears to be related, in part, to the density of the visual field loss present. Conclusion: Confrontation visual field testing is relatively insensitive unless a moderate to dense defect is present, and as such is a poor screening test. However, when visual field defects are identified with confrontation visual field testing, the defects often are real as per the high specificity (97%)and high positive predictive value (96%).

Objective To measure and compare the visual quality in myopic patients corrected by laser in situ keratomileusis (LASIK) and rigid gas permeable contact lens (RGPCL) by using point spread function (PSF).Methods This was a prospective study.There were 2 groups of patients with middle-high myopia corrected using either LASIK or RGPCL:44 eyes of 22 patients received LASIK (group A),with the spherical equivalent (SE) (-6.84±1.65)D,while 49 eyes of 25 patients corrected by RGPCL (group B),with the SE(-6.43±1.59)D.The changes of the modulation transfer function (MTF) in their eyes were evaluated before and 3 months after LASIK in group A,before and after the fitting of RGPCL in group B by using the PSF examination under conditions of 3 mm and 6 mm pupil diameters respectively.The changes of PSF in each group before and after correction were compared and the differences between groups were statistically analyzed with paired samples t test and analysis of covariance.Results ① The MTF values at low-middle spatial frequencies were decreased 3 months after LASIK (3 nun pupil diameter,2.98～23.81 cpd; 6 mm pupil diameter,2.98～9.42 cpd,P＜0.01),which was a statistically significant decrease,whereas the changes of MTF at high frequencies were not significant.②Under the condition of 3 mm pupil diameter,the MTF values at high spatial frequencies were increased after fitting of RGPCL (18.85～37.70 cpd,P＜0.05),whereas at low-middle frequencies the difference was not significant.Under the condition of 6 mm pupil diameter,the MTF values were improved at all spatial frequencies after RGPCL (2.98～37.70 cpd,P＜0.05).③The changes of MTF values at all spatial frequencies in the RGPCL group were better than those in the LASIK group (P＜0.05).Conclusion LASIK can deteriorate the visual quality of myopic patients in the early stage after surgery,whereas RGPCL can improve it.The visual quality of myopic patients corrected by RGPCL is better than that of the early stage after LASIK. Key words: Myopia; Keratomileusis,laser in situ; Contact lenses,rigid gas permeable; Point spread function

To monitor changes in corneal structure and level of inflammatory mediators in tears of myopic patients following orthokeratology (OK) and laser in situ keratomileusis (LASIK). Sixty-two myopic subjects were analyzed in this prospective study. Thirty-two had worn Paragon CRT contact lenses and 30 underwent standard LASIK. Thirty-two control subjects were also recruited. Pachometry and corneal topography were performed 12 months after both interventions. Tears were collected and assayed using ELISA for IL-6, IL-8, matrix metalloproteinase-9 (MMP-9), and epidermal growth factor (EGF). Corneal power decreased in the central area and increased in the paracentral area. Simultaneously, there was a central corneal thinning with mid-peripheral thickening for OK. No changes were observed for LASIK. In comparison with controls, IL-6, IL-8, MMP-9, and EGF levels were increased significantly for OK (P < 0.01). Only MMP-9 (P < 0.01) and EGF (P < 0.01) were increased for LASIK. Pro-inflammatory response was found to be associated with the degree of myopia in the OK group. The MMP-9 and EGF upregulation was linked to the presence of iron deposition in both groups, whereas increased levels of EGF were connected with the presence of myopic regression after LASIK. Both interventions involved important tissue reshaping. The physical presence of a reverse geometry contact lens caused certain markers to change significantly in comparison with no lens wear or LASIK in the long-term response. MMP-9 was significantly higher in tears of subjects presenting iron deposition after OK or LASIK, and EGF levels seemed to play an important role in postoperative refractive outcomes after LASIK.

To compare, in the same individuals, the safety and efficacy of laser in situ keratomileusis (LASIK) in eyes with and without previous retinal detachment surgery. In a prospective clinical trial, seven myopic patients who had previously undergone scleral buckling surgery in one eye underwent conventional LASIK surgery in both eyes. Uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), refraction, Orbscan topography and pachymetry were recorded before and 1, 3, 6 and 12 months after surgery. The eyes were divided into two groups: group 1 consisted of eyes that had undergone previous surgery for retinal detachment, and group 2 consisted of the fellow eyes of the same patients, which had not undergone any previous ocular surgery. Student's t-test for match-paired data was used to evaluate the significance of differences. LASIK was performed successfully in all patients. The UCVA improved in all eyes in both groups. The mean change in the spherical equivalent between 1 and 12 months after LASIK surgery was 1.7 +/- 1.1 and 0.6 +/- 0.5 diopter in groups 1 and 2, respectively (p = 0.019). LASIK may be considered for treatment of myopia in eyes that have had previous surgery for retinal detachment. However, the risk of regression may be higher in such eyes than in eyes with no previous scleral buckling surgery.